An aerial manipulator is a robotic system, which has the capacity to fly and at the same time to manipulate objects in its environment by applying reasonable forces and torques. Most commonly they consist of a flying robot and at least one manipulator arm. In such robots, the great workspace and the agility of aerial robots meet with the dexterity of conventional manipulators. This system breaks ground to many different robotic applications, e.g., pick and place, aerial physical interaction, and aerial grasping. Although aerial manipulators open new doors for various robotic tasks, their control and motion planning is not trivial, since they are an interconnection of multiple nonlinear robotic systems. For this reason, it is important to analyze their system dynamics and develop control algorithms dealing not only with the problem of tracking the outputs we are interested in, but also with the internal dynamics of the system and how they are coupled with each other.